This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:    ACK acknowledgement    AP access point    AUC authentication center    CAP contention access period    CFP contention free period    CP cyclic prefix    CRC cyclic redundancy check    DFT discrete Fourier transform    DL downlink    FFT fast fourier transform    GI guard interval    MAC medium access control    MCC mobile country code    MCN mobile network code    ML maximum likelihood    MNO mobile network operator    MU macro urban    OFDM orthogonal frequency domain multiplex    PCF point coordination function    PP-MAC probe and pull medium access control    PSMP power save multi-poll    PHY ACK physical layer acknowledgement    QoS quality of service    RIFS reduced interframe space    SCM spatial channel module    SIFS short inter-frame space    SNR signal to noise ratio    SPI stateful packet inspection    STA station    TSPEC traffic specification    UL uplink    VLR visitor location register    VNO visitor network operator    WLAN wireless local area network
The MAC layer is a sub layer of the data link layer as specified in the seven-layer OSI model (layer 2) and the four-layer TCP/IP model (layer 1). The data link layer provides addressing and channel access control mechanisms that make it possible for multiple terminals or network nodes to communicate within a multiple access network that incorporates a shared medium, such as wireless local area networks (WLAN).